黄山松生理生态特性研究

Physiological characteristics of Pinus taiwanensis

应用L i-6400于春、夏、秋、冬四季的晴天对黄山松的光合特性和光合日进程进行观测,同步测定细胞间隙CO2浓度、气孔导度、光合有效辐射、空气相对湿度等对光合日进程的影响。结果表明,黄山松的光补偿点为110μmol.m-2.s-1,光饱和点约为1 099μmol.m-2.s-1,表观光合量子产额为0.017左右;说明黄山松具有阳生的特点,对光能的生态适应范围较广;同一季节黄山松的光合速率都具有明显的日变化,春、夏、秋季呈双峰型,均有光合“午休”现象;多元回归分析结果表明:对光合速率影响最大是生理因子,如细胞间隙CO2浓度和气孔导度;生态因子如光合有效辐射、相对湿度、大气CO2浓度等在不同季节对黄山松的影响程度各不相同。以春季一年生针叶为例,其间的相关性可用以下回归方程表达:Y=4.70+21.62Xcond-0.02Xci+0.05XRH-0.0004XPAR。

The photosynthetic rate of needles ofPinus taiwanensis was measured in sunny days at different seasons by using Li-6400 photosynthetic system （the trees were selected in a natural community at 1 400 m above sea level） in Huangshan mountains. The effects of physiological factors （stomatal conduction, CO2 concentration in cell clearance） and ecological factors （photosynthetic active radiance, air temperature, relative humidity, etc. ） were determined as well. The results are as follows ： The light compensation point and saturation point of needles in Pinus taiwanensis are 110 μmol·m^-2·s^-1 and 1 099μmol·m^-2·s^-1 ,respectively, and the apparent quantum yields is 0. 017,indicating this tree is a typical intolerant species. The photosynthetic rates have obvious diurnal changes; their curves are double-peaked in spring and summer, and have photosynthetic depression at midday. Regression analysis showed that factors affecting photosynthetic diurnal changes were CO2 concentration in cell clearance （Ci） and stomatal conduction （Cond）, followed by photosynthetic active radiance, relative humidity et al. For example,. the Multivariable regulation for one-year needle in spring season could be written as Y=4.70＋21.62Xcond-0.02Xci＋0.05XRH-0.0004XPAR.